#include <Riostream.h>

#include "TFile.h"
#include "TTree.h"
#include "TBrowser.h"
#include "TH2.h"
#include "TRandom.h"
#include "TROOT.h"
#include "TString.h"

// This example is a variant of hsimple.C but using a TTree instead
// of a TNtuple. It shows :
//   -how to fill a Tree with a few simple variables.
//   -how to read this Tree
//   -how to browse and analyze the Tree via the TBrowser and TTreeViewer
// This example can be run in many different ways:
//  way1:  .x macroTree1.C    using the CINT interpreter
//  way2:  .x macroTree1.C++  using the automatic compiler interface
//  way3:  .L macroTree1.C  or .L macroTree1.C++
//          macroTree1()
// One can also run the write and read parts in two separate sessions.
// For example following one of the sessions above, one can start the session:
//   .L macroTree1.C
//   tree1r();
//
//  Author: Rene Brun
//  Modified: Christian Stratowa

class ClassA {
//class ClassA: public TObject {

   private:
      Float_t fPx; 
      Float_t fPy; 
      Float_t fPz; 

   public:
      ClassA() {}
      virtual ~ClassA() {}

      void    SetPx(Float_t px) {fPx = px;}
      void    SetPy(Float_t py) {fPy = py;}
      void    SetPz(Float_t pz) {fPz = pz;}
      Float_t GetPx()     const {return fPx;}
      Float_t GetPy()     const {return fPy;}
      Float_t GetPz()     const {return fPz;}

#if !defined (__CINT__) || defined (__MAKECINT__)
      ClassDef(ClassA,1)
#endif
};

class ClassB: public ClassA {

   private:
   Double_t fRandom;
   TString  fString;

   public :
      ClassB()          {}
      virtual ~ClassB() {}

      void SetRandom(Double_t rd)     {fRandom = rd;}
      void SetString(const char *str) {fString = TString(str,32);}
      Double_t    GetRandom()   const {return fRandom;}
      const char* GetString()   const {return fString.Data();}

#if !defined (__CINT__) || defined (__MAKECINT__)
      ClassDef(ClassB,1) //ClassB
#endif
};

class ClassC: public ClassB {

   private:
   Int_t fEvent;

   public :
      ClassC()          {}
      virtual ~ClassC() {}

      void  SetEvent(Int_t ev) {fEvent = ev;}
      Int_t GetEvent()   const {return fEvent;}

#if !defined (__CINT__) || defined (__MAKECINT__)
      ClassDef(ClassC,1) //MainFrame
#endif
};

#if !defined (__CINT__) || defined (__MAKECINT__)
ClassImp(ClassA);
ClassImp(ClassB);
ClassImp(ClassC);
#endif

void tree1w(Int_t size)
{
   //create a Tree file tree1.root
   cout << "------tree1w------" << endl;
   
   //create the file
   TFile f("tree1.root","recreate");

   // create new tree
   TTree t1("t1","a simple Tree with simple classes");
   ClassC *myC = new ClassC();
   t1.Branch("BranchC", "ClassC", &myC, 64000, 99);
   
   //fill the tree
   Float_t px, py, pz;
   Double_t random;
   TString str;
   Int_t ev;
   for (Int_t i=0;i<size;i++) {
     gRandom->Rannor(px,py);
     pz = px*px + py*py;
     random = gRandom->Rndm();
     str = TString(""); str += random;
     ev = i;

if(i<4)cout << "px = " << px << "  random = " << random << "  str = " << str << endl;

     myC->SetPx(px);
     myC->SetPy(py);
     myC->SetPz(pz);
     myC->SetRandom(random);
     myC->SetString(str);
     myC->SetEvent(ev);

     t1.Fill();
  }
  
  //save the Tree header. The file will be automatically closed
  //when going out of the function scope
  t1.Write();
}

void tree1r()
{
   //read the Tree generated by tree1w and fill two histograms
   cout << "------tree1w------" << endl;
   
   //note that we use "new" to create the TFile and TTree objects !
   //because we want to keep these objects alive when we leave this function.
   TFile *f = new TFile("tree1.root");

   ClassC *myC = 0;
   TTree  *t1  = (TTree*)f->Get("t1");
   t1->SetBranchAddress("BranchC",&myC);
   
   //read all entries and fill the histograms
   Float_t px, py, pz;
   Double_t random;
   TString str = "";
   Int_t ev;
   Int_t nentries = (Int_t)t1->GetEntries();
   for (Int_t i=0;i<nentries;i++) {
     t1->GetEntry(i);

     px = myC->GetPx();
     py = myC->GetPy();

     random = myC->GetRandom();
     str    = myC->GetString();
if(i<4)cout << "px = " << px << "  random = " << random << "  str = " << str << endl;
  }
}   

void macroTree1(Int_t size = 10000) {
   tree1w(size);
   tree1r();
}